The present invention relates to a technology for data backup.
For example, according to Japanese Patent Application Laid-open No. 2005-332067, a disk array device performs data update after snapshot acquisition to an update data storage disk device that is a storage area physically separated from a disk device that stores the original data.
A method by which a backup server reads data from a storage device that is a backup source and writes the data that were read into a storage device that is a backup destination is an example of backup. However, with this method, for example, when the backup performance of the backup server is inferior to that of the storage device that is the backup source and/or backup destination, the backup performance of the backup server becomes a bottleneck.
A method of acquiring a snapshot of a logical volume at a snapshot acquisition time and taking the snapshot as a backup source can be considered as another backup method. However, if the snapshot is taken as a copy (referred to hereinbelow as “volume copy”) of the logical volume itself at a snapshot acquisition time, when there are a plurality of snapshot acquisition times, the number of volume copies has to be equal to the number of snapshot acquisition times. As a result, the consumption of storage resources is increased.